Grinding apparatus



July 18, 1944. L. w. ENHOLM 2,353,956

- GRINDING APPARATUS Filed April 25, 1942 3 Sheets-Sheet 5 )voe Invenio Patented July 18, 1944 UNITED STATES PATENT OFFICE! GRINDING APPARATUS Lewis W. Enholm, Wollaston, Mass, assignor to William H. Field, doing business as William H. Field Company, Boston, Mass.

Application April 25, 1942, Serial No. 440,522

3 Claims. (Cl.-51--92) This invention relates to sharpening or grinding apparatus, and more particularly to mortise chain cutter sharpening apparatus.

The invention and its aims and objects will be readily understood from the following description, taken in connection with the accompanying drawings, of one embodiment of the invention herein given for illustrative purposes.

In the drawings:

Fig. 1 is a front elevationof one illustrative embodiment of the invention;

Fig. 2 is a top plan view of the embodiment shown in Fig. 1, partly in section on line 22 of said figure;

Fig. 3 is a top plan view of the embodiment of the invention shown in Fig. 1;

Fig. 4 is a longitudinal section on line i@ of Fig. 3;

Fig. 5 is an enlarged longitudinal section on line 55 of Fig. 3;

Fig. 6 is a sectional elevation on line 66 of Fig. 4, on a somewhat enlarged scale;

Fig. 7 is a cross section on line 'l! of Fig. 5;

Fig. Sis a side elevation of the parts shown in Fig. 3, on a somewhat enlarged scale. certain parts being shown in section on lines 8-8 and 8a8a of Fig. 7;

Fig. 9 is a side elevation of the sprocket with the mortise chain thereon, on a somewhat enlarged scale as seen from the right of Fig. 1, and

showing the general operative position of the grinding or sharpening tool;

Figs. 10 and 11 show how the hook or angle of the cutting edge of cutters may be varied as desired.

In the illustrative embodiment of the invention herein shown, the frame 2 is provided in front with a vertical guide-slot l, in which a correspondingly shaped guide-rib 5. provided upon a support or carriage 8, has a sliding fit. Said carriage 8 carries a clamping bearing!!! for a shaft l2. To the projecting ends of said shaft l2 are secured the free ends of arms M of a bracket 66 which supports the means for presenting the mortise chain to said grinding or sharpening tool. said means herein illustratively comprising a shaft l8 slidingly and rotatably mounted in said bracket and having a reduced end portion it! upon which is fixedly secured a sprocket 22 (see Fig. 6). A rod 24 is provided at one end with a reduced. screw-threaded portion 25 having screwthreaded engagement with an axial bore 28 in said end portion 25) of said shaft I8. Tightening the screw-threaded engagement of said rod 2 with said shaft i8 will firmly secure the former to the latter and will firmly clamp said sprocket 22 to said shaft between a collar 36 on said rod 24 and a shoulder 32 on said shaft l8 so that said sprocket will slide and turn with said shaft and rod 2G. The latter may be provided at its free end with a wheel 34 to facilitate manipulation thereof.

The sharpening or grinding means herein illustratively comprises a sharpening or grinding tool, which may illustratively consist of a disk shaped grinding wheel 36 positioned above and to the left, see Fig. 1, of the said sprocket 22 when said rod 24 is in its extreme position to the right, as shown in said figure. Said grinding wheel may be driven by any suitable driving means. Herein said wheel is conveniently driven by an electric motor 38, mounted upon the frame 2, and preferably provided with a hood 40 enclosing the same sufiiciently to protect the operator from flying particles from said wheel and the work.

To grind the cutters of a mortise chain, the latter, herein designated by 4 I, is suspended upon said sprocket22 (see Fig. 1) with teeth of the latter in mesh with links of said chain, and grinding or sharpening of the cutter teeth is effected by sliding said rod 24 and shaft 18 back and forth so as to reciprocate said sprocket and chain carried thereby past said rotating grinding wheel 36, and turning said rod, shaft and sprocket step by step so as to bring all the cutters of said chain successively into grinding position relatively to said disk (see Fig. '7)

Heretofore the mortise chain to be sharpened was sustained only by the sprocket from which it hung perfectly free, with the result that there was a complete lack of stability or control of the chain and its cutters. To remedy this it has therefore always been customary for the operator to grasp and hold the mortise chain with one hand while operating the rod 24 with the other, during the sharpening. operation. In order to be effective, however, this required that the mortise chain be grasped as closely as feasible to the sprocket 22, which not infrequently resulted in injury to the operators hand. Furthermore neither the position of the chain nor the tension exerted thereon was uniform during the sharpening operation so that all the cutters of the chain were not ground uniformly and were therefore not of the same length and the same degree of hook. As a result-of this lack of uniformity in the sharpening of the cutters some of the latter could not perform their share of the mortising operation, which detracted from the appearance and perfection of the mortise. The sharpening of the cutters as heretofore practised required an expert operator and even so the result was not uniformly satisfactory.

One of the objects of the present invention is to remedy these defects and to that end means are provided for controlling the mortise chain during the cutter grinding or sharpening operation. The position of the mortise chain may thus be controlled, for example with relation to the means for presenting the chain to the cutter grinding or sharpening means, so that said position shall remain substantially the same during the sharpening of all the cutters of the chain. Preferably the arrangement will be such that the chain will be under tension, and means may be provided in accordance with the present invention whereby the tension may be adjusted or regulated as may be desirable; the tension may be adjusted so that it shall be the same as that to which the chain will be subjected while in operation on the mortising machine.

Referring to Figs. 1 and 6, said means for controlling the position of the mortise chain herein illustratively comprises a bar 42 loosely suspended by one end 44 from said shaft I8, for example, and between said sprocket 22 and a collar 46 upon said shaft. A block 48 provided with a guide roll 49 is slidingly mounted upon said bar 42. A second block-50 is also mounted upon said bar 42 and is adjustable lengthwise thereof, a set screw 52 serving to clamp said block 50 in adjusted position. This bar acts as a support. A spring 54 surrounds said bar and bears with one end against block 48 and with the other against block 50. Means is thus provided for putting the chain under tension or for holding it yieldingly in position. The guide roll 49 will preferably be centered, or crowned or biconical in cross section, to accommodate chains of different width.

The lower end of said bar 42 engages a longitudinal slot or guideway 56 in a slotted mem-' ber 58 rigidly secured to a fixed portion of the apparatus. Herein said slotted member is.conveniently secured to the rear surface of the hood 40 of the grinding tool, by a rod or bar 60. Means is thus provided to guide said control ling means and prevent bodily movement of the mortise chain transversely to shaft I8, while permitting said chain to move with said shaft I8 in its longitudinal movement as required to move the chain and sprocket past the grinding tool in the grinding orsharpening operation.

Means may be provided to facilitate adjustment of the tension to be exerted upon said mor-v tise chain 4|. Herein said means may conveniently comprise an index or pointer 62 carried by one of the blocks 48 or 50, and a tension scale 64 carried by the other of saidtwo blocks and bearing graduations indicative of different degrees of tension.

Said shaft I8 is slidablev and rotatable in a bearing 68, and a further bearing 68 is provided to be engaged by the inner end of said shaft I8 when the latter is moved to the left,

(see Fig. Said bearing 68 is contained in a tubular member I0 rotatably fitted at its inner end within an enlarged part 12 of saidbearing 66, and herein the rotatable tubular member is provided interiorly with longitudinal grooves I6. Said shaft I8 is providedwith a head I8 upon the outer surface of which are splines 80, parallel to said grooves 16 and adapted to slide into locking engagement with the latter to guide said shaft I8 and the cutter to be sharpened in the right paths when the sprocket is moved past the grindingtool to sharpen said cutter, and to lock said shaft I8 and sprocket 22 against rotation during this operation. The spacing of the cutters on the mortise chain is such that when said chain is on the sprocket 22 a cutter will be opposite each sprocket tooth and opposite each space between two sprocket teeth. There should therefore be twice as many grooves I6 and twice as many splines 80 as there are teeth on the rial 82.

sprocket. Herein the sprocket used has 7 teeth and there are therefore 14 grooves I6 and 14 splines 80. Whenever the splines are in mesh with grooves I6 a cutter of the mortise chain on the sprocket will be in position to be moved past the grinding tool and be sharpened.

That portion of shaft I8 between the upper end 44 of bar 42 and the right end (see Figs. 1 and 5) of said bearing 66 will preferably be enclosed by a seal of any suitable flexible mate- The ends of said seal 82 are fitted over flanges B4 and 86 respectively on said bearing 66 and on said top portion 44 of said bar 42. Said shaft I8, its bearing 66 and the grooves 16 and splines 80 will thus be kept free from dust and dirt and particles cast off from the grinding wheel 36 and from the mortise chain cutters in the grinding operation. Grooves 88 and 90 may be provided in said flanges 84 and 86 respectively, and the end portions of said seal may be tightly bound in said grooves by bands or wires 92, 94 to provide a very thorough seal. An oil cup for shaft I8 is shown at .96; other oil cups (not shown) are provided at all points where required.

Vertical adjustment of the sprocket 22 and associate parts is provided for by suitable means, herein illustratively comprising a regulating screw 98 in threaded engagement with a vertical bore provided in the top of frame 2 (see Fig. 1), and suitably mounted in an arm I00 of the carriage 8. A wheel I02 will preferably be provided to facilitate manipulation of said screw 98. Means are also provided for varying the hook or angle of the cutting edge imparted to the cutters of the mortise chain. Hereinsaid means illustratively comprises a relatively fine threaded adjusting screw I04 in screw threaded engagement with a boss I06 upon the under side of bracket I6. The free end of said screw I04 abuts against the front face of said guide rib or slide 6. By loosening the clamping device comprising handle I 08 and clamping screw IIO extending through flanges H2 and II 4 of the clamping bearing I 0, the shaft I2 carrying said bracket will be freed, thus permitting swinging adjustment of said bracket I6 about the axis of said shaft I0 to vary the hook or angle imparted to the chain cutters, whereupon said clamping device may be tightened to lock said bracket IS in adjusted position. A scale I I6 may be provided upon the upper surface of one of the arms I4, and a line H8 upon the adjacent edge portion of the bearing I0, to facilitate adjustment of the parts to obtain the desired hook or angle of the cutter edge (see Fig. 3).

Means may also be provided for varying the length of the cutters of the mortise chain. Herein this is provided for by adjustment of said tubular member ID about its longitudinal axis by rotating said tubular member 10 and thus angularly to adjust said guide grooves 16 clockwise or contraclockwise. Said member 10 is held in adjusted position by clamping means comprising a shoe I20 slidably mounted in a recess provided in said bearing 66 and slidable along a screw I22 fixed in the wall of said bearing 66 opposite the inner end of said shoe I20. The free end of said screw projects beyond the right end (see Fig. 8) of said shoe I20 and is in screw threaded engagement with one arm of an angular hand lever I24. By turning said lever I24 in the proper direction said clamp will be released and said member I0 may be rotated about its axis angularly to adjust said grooves I6 to vary the length of the mortise chain cutters, and member then may again be clamped in its new position. To facilitate angular adjustment of said grooves 16, said tubular member 10 may be knurled exteriorly as shown at I26 in Fig. 1.

The operation is briefly as follows:

The mortise chain having been placed upon the sprocket 22 and the guide roll 49, and all adjustments as above set forth, having been made, the motor is started thus setting the grinding wheel in operation. The shaft 58 being in its extreme right position, with the sprocket 22 sub-- stantially in the position shown in Fig. l, operator grasps the wheel 34 and slides rods ii and shaft l8 to the left in said figure. In this movement splines 80 upon head it? of shaft 93 first engage grooves 16 in member it, which is immobilized by the clamping device 5 I22, I24, as above described, and then siide along in said grooves as the sprocket 22 with the mortise chain thereon moves past the grinding wheel 35 to sharpen a cutter by contact with the latter, said cutter bein guided in the correct path by engagement of said splines 86 with said grooves 16. The operator now draws rod 2 5 and shaft l8 to the right (see Fig. 1), thus disengaging splines 88 from grooves 76, the sprocket 22 occupying substantially the position shown in said Fig. 1. The operator then turns said shaft and sprocket clockwise through the distance separating grooves Hi from one another. This brings each of the splines 88 in line with that groove 75 which follows the groove '13 it was previously in engagement with, so that by now moving shaft l8 and sprocket 22 to the left, the next mortise cutter will be guided past the grinding wheel and sharpened by contact with the latter. This same procedure is followed for the next cutter on the mortise chain and so on until all the cutters on said chain have been sharpened. During this entire operation the mortise chain and the cutters thereon are held in correct position by the mortise chain controlling means, and preferably under the same tension, substantially, as that under which said chain will be held in the mortising machine during the mortising operation.

Applicants invention is a distinct advance in the art and a valuable contribution thereto. The mortise chain is under perfect control during the sharpening operation, thereby ensuring uniform grinding and sharpening of the cutters of said chain, and consequently more uniform and perfect work in the mortising operation. Any seven tooth, standard sprocket may be used. Instead of using both hands, as was heretofore necessary, the operator need use but one. The operator need not be an expert, as heretofore, and the sharpenin operation is from twice to three times as fast as heretofore. Operating with shaft l8 and the mortise chain under tension, preferably the same tension as that to which said chain is subjected in the mortising machine, ensures longer life for the mortise chain, greater accuracy and smoother operation.

I am aware that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof, and I therefore desire the present embodiment of said invention to be considered in all respects as illustrative and not restrictive, reference being had to the appended claims rather than to the foregoing description to indicate the scope of the invention.

I claim:

1. Apparatus for sharpening cutters of endless cutter chains, comprising cutter sharpening means; a sprocket and a guide roll over which to train an endless cutter chain; said sprocket and guide roll being adapted to move relatively to said cutter sharpening means to present a cutter of said chain to said cutter sharpening means; supporting means for said guide roll, said supporting means comprising a member carrying said guide roll and movable toward and from said sprocket; a second member adjustable relatively to said first named member upon said supporting means; a spring adapted to bear with its opposite ends against said two members respectively; means for securing said second member in adjusted position upon said supporting means; means for moving said sprocket relatively to said cutter sharpening means to sharpen a cutter of a cutter chain upon said sprocket; and means for moving said guide roll relatively to said sharpening means with said sprocket.

2. Chain cutter sharpening apparatus comprising a, cutter sharpening tool; a cutter chain carrier comprising a shaft and a sprocket mounted on said shaft, said shaft being rotatable and slidable longitudinally to present a chain cutter on said sprocket to the operation of said cutter sharpening tool; a support for said shaft; locking means, including corresponding projections and grooves on said shaft and its support, concentric with said shaft and coacting therewith positively to hold said shaft against rotation during the cutter sharpening operation, said shaft being rotatable relatively to said locking means when said cutter chain carrier is in a non-sharpening position; and cutter chain tensioning means, including means to hold said chain under resilient tension, adapted to engage said chain, said shaft being operatively connected to said cutter chain tensioning means, whereby said shaft will move said cutter chain tensioning means with said sprocket when said shaft is moved longitudinally.

3. Chain cutter sharpening apparatus comprising a cutter sharpening tool; a cutter chain carrier comprising a shaft and a sprocket mounted on said shaft, said shaft being rotatable and slidable longitudinally to present a chain cutter on said sprocket to the operation of said sharpening tool; a support for said shaft; looking means, including corresponding projections and grooves on said shaft and its support, concentric with said shaft and coacting therewith positively to hold said shaft against rotation during the sharpening operation, said shaft being rotatable relatively to said locking means when said cutter chain carrier stands in non-sharpening position; and cutter chain tensioning means adapted to engage and to keep said chain under resilient tension, said shaft being operatively connected to said cutter chain tensioning means, whereby said shaft will move said cutter chain tensioning means with said sprocket when said shaft is moved longitudinally; and guiding means to guide said cutter chain tensioning means when moved by said shaft.

' LEWIS W. ENHOLM. 

